Selective epitaxial growth (SEG) provides growing of semiconductor layers locally through a patterned dielectric mask layer. Selective epitaxial growth of layers is particularly interesting in semiconductor industry. This is due to the fact that, in the manufacturing of semiconductor devices, depending on the layer to be grown and on the device to be manufactured, selective epitaxial growth of layers may be used. Furthermore, SEG can be followed by epitaxial lateral overgrowth (ELOG), which may allow for improved device manufacturing and device performance.
Growth of Group III-nitride layers are interesting particularly for the manufacturing of power devices and Light Emitting Diode (LED) application and particularly for enhancement mode devices based on GaN technology. Providing a p-doped GaN (p-GaN) layer in the structure of a p-GaN High Electron Mobility Transistor (HEMT) device has, typically, been done by growing a layer of p-GaN on the barrier layer, which is typically an AlGaN layer, followed by patterning and etching of this layer. However, there are difficulties associated with this approach of providing a p-GaN layer. The difficulties arise in etching the p-GaN layer selective to the barrier layer. Additionally, exposure of the surface of the barrier layer in the region between the gate region and the source/drain region, which is typically referred to as the access region, to plasma etch, creates a difficulty to use high temperature dielectric deposition since that region cannot be passivated after the etch step.
This problem can be remedied by the method disclosed in EP 2 602 827 B1. Selective regrowth of p-GaN layer in a recessed gate region is disclosed, where an in-situ grown SiN layer is present having an opening to define the recessed gate region. It is, however, a major challenge to grow p-GaN by selective epitaxy in an opening in the manufacturing of HEMT devices. This is due to the fact that it becomes difficult to control the growth rate and improve the surface morphology of p-GaN layer.
There is, therefore, a need in the art to improve SEG and ELOG (Epitaxial Lateral Over Growth) of Group III-nitride material such that device performance would not be challenged when used in the manufacturing of devices in semiconductor industry.